Ikuko Hayashi

Renal Hemodynamic Changes Induced by Captopril and Angiotensin-Converting Enzyme Gene Polymorphism

We studied the relationship between renal hemodynamic changes induced by a single acute administration of captopril (50 mg p.o.) and angiotensin-converting enzyme (ACE) gene insertion/deletion (I/D) polymorphism in 27 healthy human volunteers, 7 with DD genotype, 10 with ID, and 10 with II genotype. The increase in effective renal plasma flow (p < 0.02) and the fall in renal vascular resistance (p < 0.01) in response to captopril were significantly less in subjects with the DD genotype than in subjects with the other genotypes. These data suggest that intrarenal ACE inhibition by captopril differs according to ACE gene ID polymorphism in healthy humans.

Renal Involvement in POEMS Syndrome

We describe a patient with POEMS syndrome whose renal biopsy specimen also showed nephropathy. Immunoelectron microscopy of the renal biopsy revealed the localization of immunoglobulin (IgA and lambda light chain) in the subendothelial space of the glomerular capillaries, a previously unrecognized finding. We conclude that the renal pathology in POEMS syndrome is unusual and distinct from microangiopathic glomerular involvement or idiopathic mesangiocapillary glomerulonephritis.

Effects of an oral protein load on glomerular filtration rate in healthy controls and nephrotic patients.

Glomerular filtration rate (GFR), effective renal plasma flow (ERPF) and humoral factors were simultaneously examined before and after a 50-gram oral protein load in 12 healthy controls and 12 nephrotic patients. The protein load led to rises in GFR with unchanged filtration fraction in both groups although the rate of increase in GFR was greater in the former. The levels of blood urea nitrogen, serum osmotic pressure, plasma glucagon and serum insulin, but not plasma angiotensin II, were significantly elevated following the protein load. The increase in GFR after the protein load appears to be mainly caused by increased ERPF and afferent arteriolar vasodilation.

Effect of Prostaglandins on Renal Function in Uninephrectomized Humans

We examined the effects of unilateral nephrectomy (UN) and administration of indomethacin in 15 healthy humans. Glomerular filtration rate (GFR), effective renal plasma flow (ERPF), urine flow, sodium and potassium excretions, urinary excretion rate of prostaglandin E2 (PGE2) and 6-keto prostaglandin F1 alpha (6-keto PGF1 alpha) in the remaining kidney were all significantly (p < 0.01) increased 10 days after UN. Indomethacin administered at 75 mg/day for 3 days abolished the increase in GFR, ERPF and sodium excretion with reduced urinary excretion rate of PGE2 and 6-keto PGF1 alpha but not the increase in urine flow and potassium excretion. These findings suggest that renal prostaglandins may play a role in renal functional adaptation following UN.

Renal Angiotensin-Converting Enzyme Localization in Diabetic Rats and the Effect of Low Protein Diet

Recent evidence suggests a role of angiotensin-converting enzyme (ACE) in diabetic nephropathy. The effect of diabetes and low protein diet on renal immunohistochemical ACE localization was studied in streptozotocin-induced DM rats. Immunohistochemical ACE localization was reduced in DM rats, and a low protein diet partially resolved this abnormality while inhibiting the progression of diabetic nephropathy.

Dietary treatment in hemodialysis patients, focused on dietary protein restriction.

血液透析患者における食事療法とくに低蛋白食の有用性について検討した. 対象は原則としてP吸着剤を投与されていない安定期血液透析患者17名とした. 入院前のfree dietと, 入院後2週間施行した低蛋白・高エネルギー・低P食 (蛋白質40g/日, エネルギー2,200kcal/日, NaCl 3g/日, P含有530mg/日) とを, 血液尿素窒素 (BUN), 血清P値, 血清Ca値, Ca×P積値, 血清総蛋白等の血液生化学データにより比較した. 食事療法後, BUNは75±17mg/dlから57±15mg/dlへ, 血清P値は7.5±2.1mg/dlから4.5±1.3mg/dlへ, Ca×P積値は69±22から44±12へいずれもP<0.01の有意な低下を認めた. 血清Ca値は食事療法後有意に (P<0.01) 上昇した. 血清総蛋白には有意な変化を認めなかった. 以上の結果から, 血液透析患者における低蛋白・高エネルギー・低P食は, BUNの改善のみならず, P吸着剤を投与せずにPコントロールを行い得ることが示された.